Gallery

The "new or updated" flag helps keep track of a Gallery. But sometimes
albums are added for technical reasons (reorganizing a gallery for example)
and showing them as "new or updated" does not make sense, especially in the
RSS feed.

A way to solve that problem would be to add a 'never show as new or
updated' property to the album class. Default value would be "false" which
is the current behavior. Setting it to "true" via a checkbox in the album
properties would let G2 know that the "new or updated" should not be shown
for this item and that it should not appear in the RSS feed.

Impacts as far as I understand :
- Extra field in the album record
- Extra checkbox in the album properties interface
- Extra check in the RSS code
- Extra check in the flag icon display code